Scaling of Nonlinear Susceptibility in MnCu and GdAl Spin-Glasses

Abstract

SQUID measurements of susceptibility $\ensuremath{\chi}$ versus field $H$ are fitted by $\ensuremath{\chi}={\ensuremath{\chi}}_{0}\ensuremath{-}{\ensuremath{\chi}}_{1}{H}^{a\ensuremath{-}1}$ at a given temperature $T$, for two classic spin-glasses: 4.6% Mn in Cu (polycrystalline) and 37% Gd in Al (amorphous). ${\ensuremath{\chi}}_{1}(T)$ shows a much stronger anomaly than ${\ensuremath{\chi}}_{0}(T)$, while $a(T)$ has a minimum at the freezing temperature ${T}_{f}$. The data can also be scaled according to ${\ensuremath{\chi}}_{0}\ensuremath{-}\ensuremath{\chi}={H}^{\frac{2}{\ensuremath{\delta}}}f(\frac{(T\ensuremath{-}{T}_{f})}{{H}^{\frac{2}{\ensuremath{\phi}}}})$ with $\ensuremath{\delta}=5\ifmmode\pm\else\textpm\fi{}1$ and $\ensuremath{\phi}=4.5\ifmmode\pm\else\textpm\fi{}0.5$.